


it's like an angel sighing

by WattStalf



Series: Commissions [107]
Category: Fire Emblem Series, Fire Emblem: Fuukasetsugetsu | Fire Emblem: Three Houses
Genre: Anal Fingering, Anal Sex, F/M, Masturbation, Religion Kink, Vaginal Sex, commission
Language: English
Status: Completed
Published: 2020-04-03
Updated: 2020-04-03
Packaged: 2021-03-01 02:14:10
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 5,036
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/23463781
Author URL: https://archiveofourown.org/users/WattStalf/pseuds/WattStalf
Summary: Byleth has adjusted well to life at the monastery, but Rhea fears that he does not take his religious studies seriously, and hopes to remedy that.
Relationships: My Unit | Byleth/Rhea
Series: Commissions [107]
Series URL: https://archiveofourown.org/series/1325462
Comments: 3
Kudos: 77





	it's like an angel sighing

Something has seemed off about the archbishop since the beginning. From the way his father warned him to watch out for her, to the overly familiar way she soon began talking to him, Byleth has had his suspicions about Lady Rhea for a long time. Even so, he finds it hard to stay away from her, and not just because she tries to bring the two of them closer together at any opportunity that she has.

No, the simple fact remains that there is something about her that draws him to her, an intoxicating factor that makes her impossible to ignore, which he is sure has something to do with why she is so beloved by those in the church. It would be easy enough for anyone to fall for her, to admire her from afar, and have much more selfish reasons for becoming a devout member of the church than a genuine devotion to the goddess.

Byleth has never been particularly religious. He was not raised to be, and was barely aware of the existence of a church to begin with. Coming to a place that centered around religion, and discovering that most everyone believes in the goddess, that he has been living under a rock for not knowing about all of this, was a major culture shock for him, and something that he struggled to get used to.

But for the most part, he feels that he has settled in well, even if he still does not understand most of what goes on around here. And amongst all of that is the confusion that comes with the archbishop’s presence in his life, and her attempts to develop a bond with him for reasons far beyond his understanding. He simply takes each day as it comes, though he does feel out of place at choir festivals and Saint celebration days, because he has still not made any particular commitment to the Church of Seiros.

To him, that does not seem like much of a problem, and certainly does not get in the way of his work as a professor. He tries to make sure the students maintain their good standing in the church even despite his separation from it, so he thinks that he is doing a good enough job as things are.

But what he does not realize at first is that Lady Rhea is watching him closely, and taking a particular interest in just how separate the former mercenary remains from the church. He keeps his distance from her in order to heed his father’s warnings, but he finds himself interested enough to keep admiring her from afar, somehow never noticing just how much she has her eye on him, incapable of understanding the complexity of her interest in him.

Things do not come to a head between them until Saint Seiros Day. Byleth makes sure to bring his students to celebrate in the cathedral, with prayer and song, just as they are supposed to, and then goes back to his daily routine, thinking nothing of it. He was vaguely aware of Rhea’s eyes on him during the celebration in the cathedral, but he is used to her eyes wandering to him, and used to trying to avoid her gaze despite wanting, more than anything, to look back at her and try and understand the meaning behind her gaze.

It means nothing to him until later, when he is finishing up some grading on his own, when a knight comes to knock at his door, telling him that the archbishop has summoned him to her chambers. It has been a long time since Byleth has received a direct summons from her, and he wonders why she is asking him to meet her in her room, and what the reason behind it all is. 

Though he prefers to keep his distance like he is supposed to, he definitely can’t deny a request like this from her. She is his employer and his host, and he has learned just how fearsome the church can be. He would never dare to do anything to anger her on purpose, and so he wastes no time in making his way to her chambers, feeling strange as he knocks at the door.

There are guards waiting outside, but they must already be expecting him, seeing as how they let him knock without even asking his purpose for being here, much less trying to make sure that he poses no threat to the archbishop that he is trying to visit. They just ignore him, which means that Rhea must have told them he would be coming, and not to give him a hard time.

Of course, the guards would very easily be able to break down the doors if something were to happen to her, a reminder to Byleth that he is not to try anything with her. Not that he would want to, and not that he would ever dare try to. Even so, he would not be able to judge anyone for not easily trusting him, especially with the suspicious circumstance under which he was brought here, and with the manner of his upbringing and the questions about his heritage that even he is not able to answer.

Whatever the case, he knocks and Rhea’s familiar voice soon calls out, “Is that you, professor?”

“It is,” he replies. “You wished to see me about something?”

“Very well, professor. You may enter,” she says. Upon hearing her response, the guards suddenly move into action, opening the doors to her chambers for Byleth. Inside, Rhea waits for him, smiling serenely as she beckons him.

The doors close behind Byleth as soon as he enters the room, and for a moment, he feels trapped, before telling himself that he has nothing he needs to worry about. More than likely, this is just a meeting to discuss how he has settled in at the monastery, or a change she would like for him to make to his curriculum. He has not heard stories of Rhea doing this from any of the other professors, but that does not mean it has never happened before.

Once he has reached her, she gives him a kind smile and says, “You know that today is Saint Seiros day, don’t you, professor?”

“I do,” he replies. “I took my students to the cathedral for the celebration.”

“Yes, I did see your class there. But do you know how important a day like that is for the Church of Seiros?”

If he says yes, then he may have to explain to her, when the truth is, he barely understands any of it. Instead, he says, “I’m afraid I’m not as familiar with that as I should be.”

Her smile falls, and she gives him a sad, almost mournful expression. “That is most regrettable, professor. I had hoped that your time here would show you the beauty that the church truly possesses. I had hoped that you would convert and serve as a shining example to your class and the other classes.”

“I...my apologies, Lady Rhea. It was not my intention to-”

“Today is also my birthday,” she interrupts him, taking him by surprise. “So you must understand how difficult it is for me to take time out of a day both so important to me as the archbishop, as well as a day so important to me personally, to have to confront you about your sinful ways.”

“Happy birthday,” he mumbles, because he does not know what else to say. Her eyes narrow for a split second, but return to normal so quickly that he wonders if he might have just imagined it.

“Yes, I suppose it has been a happy birthday,” she replies, rather than thanking him. “Now, would you perhaps make it even better for me?”   
“I...how so? I would do anything within my power, you know that.”

“It’s strange. You respond to me so easily, yet the teachings of the church leave you cold,” Rhea muses. “If you would like to help make my birthday better, you could at least try to embrace the religion here. I know that it would do you a world of good to let go of whatever skepticism your father may have given you.”

Byleth wants to defend his father, but he does not think that will do him much good in this situation, so he replies, “I will try, Lady Rhea. I’m sorry that it came to this, and I promise to put more effort in-”

“You are much too full of sin as you are now,” she once again interrupts him. “I have determined that that is the cause of your distractions. You can’t focus on prayer nor can you open your heart to the goddess, not in the state that you are currently in. Before you can begin ‘putting more effort in,’ you must first allow me to assist you in clearing up your distractions, and cleansing you of your sins.”

At this, Byleth begins to grow nervous. He wonders what sort of punishment he will have to undergo for this, or if there will be some sort of cleansing ceremony. Is he going to be publicly shamed for his mistakes? There had never been enough pressure on him before to take converting to the Church of Seiros seriously before now, but maybe that was because everyone else stayed in line so much that nobody knew about the punishments. Or maybe everyone other than him knew the punishments, and that is why nobody ever stepped out of line.

Byleth tries to prepare his excuses in his mind, his protests and promises, and tries to figure out what he will do from this point on to keep her convinced that he is a devout follower, that there is nothing to worry about where he is concerned. He says, “Lady Rhea, I don’t think-”

She has closed the remaining space between them, pressing a finger to his lips to silence him. “You have nothing to be afraid of, professor. This is all for your own good, and I will be the only one assisting you in this. I promise that you will feel much better after I have helped to draw out your sin and distraction.”

Before he can attempt to protest further, she has leaned forward and pressed her soft lips to his, and Byleth loses the ability to think at all. Once she pulls back from it, he can only wonder how that is supposed to make him  _ less _ distracted, when the beauty of the archbishop has always been a factor in struggling to look beyond the church itself to understand the history and religion behind it. Though he has never admitted that before, Rhea has always been a factor, and she must have noticed that by now.

“I am your biggest distraction, aren’t I?” she asks, wearing that same gentle smile that he is sure could inspire martyrs to march directly to their stakes.

“You are,” he answers honestly, and her smile only grows.

“That is understandable, professor. Not only that, but once I have finished with you, I’m sure you will understand that you can use that distraction to your benefit, if you only learn how to redirect your focus,” she says. “Once we have worked to rid you of sin, you will understand it all perfectly.”

Byleth simply nods, stunned speechless by all of it, and Rhea turns away from him. He nearly falls over from shock when she begins to undress in front of him, leaving him completely frozen in place as he watches the archbishop disrobe, her back to him. Naturally, Byleth can’t keep himself from staring, especially not with the fabric of her dress falls and catches on her hips, and she pushes it over her hips to expose her rear to him.

“L-Lady Rhea?” he finally says, his voice breaking as he does. “What are you...should I...leave?”

“No, of course not,” she says with a laugh, as if he is merely joking with her. “I want you to watch me, of course. The first step is a very important one. You must watch and you must remain seated, resisting your own temptation in the process.”

Byleth can hardly believe that this is real, but he does as she tells him and sits on the edge of her bed, watching her as she goes to get out a small bottle. Rhea is now completely naked, and somehow she walks with even more grace. The bottle contains something that resembles a salve of some sort, and she spreads it on her fingers, getting them slick before bending over right in front him.

His eyes widen as she spreads her ass cheeks and begins to work a finger inside of herself, and suddenly he understands exactly what she means by resisting his temptations. Having her presented to him like this makes it difficult not to stand up, undo his pants, and bury his cock in her ample ass, having his way with her. Byleth does not ordinarily feel such temptations, at least not to this degree, but Rhea has found a way to make it incredibly difficult for him.

She looks back at him from over her shoulder as she does it, an expression on her face like none he has ever seen before, an expression that he could only describe as lewd, which is definitely a word he never thought he would associate with the archbishop herself. But there is no other way to describe it, as she works her finger inside of her, in and out slowly at first, and then picking up the pace, moaning as she does so. Byleth stiffens as the sound, not sure how he is supposed to control himself in a situation like this.

Never has he struggled so much with self-control, and he does not know what it is about the woman in front of him that brings out this side in him, but she must be right in assuming that he needs help learning to ignore his distractions. Surely, if he is this weak, then she must be right about him needing her help.

A second finger soon follows, and her moans grow longer and deeper as she fingers her asshole, and Byleth remains stiff, fists clenched at his side as he tries to ignore his desire to have his way with her. He wants her so badly, more than he has ever wanted anything in his life, and he must have wanted her this whole time, and simply struggled to understand what his desire was until she quite literally put it in front of his face. Before now, he had never been able to explain how drawn to her he was, and had never been able to explain his distractions, but now it makes perfect sense.

“You want to sin, don’t you?” she asks, her normally serene voice becoming breathless from her efforts. “You want to sin so badly, but you know that you must maintain your self control, because it is as the goddess wills it. Because it honors the saints and the goddess they- a-ah!- served.”

Her sermon sounds strange when punctuated by her moans, but Byleth is far more enraptured than he has ever been when seated in the cathedral, though, of course, that is part of the problem that she claims she is going to solve today. He can’t bring himself to respond to her, but he is sure that he is not meant to, and that she already knows what he is going to say either way.

“Professor…” she murmurs, before correcting herself. “No, if we are before the goddess, then I should call you by your name...Byleth, then.” She pauses, working her fingers deeper and crying out rather shamelessly. “Byleth, you must learn how to control your distractions. I must do what I can to free you of your sin. You do know what this means, don’t you?”

“I-I…” He finds that he has to clear his throat, not used to speaking after being made to sit silently for so long. “My apologies, Lady Rhea, but I’m not sure what I should…”

“I want you to remain seated,” she says, “but I want you to undo your pants as well. You understand, don’t you?”

Silently, he nods and does as she tells him, his erection standing tall now that it is exposed. Rhea looks at him with something like hunger in her eyes before handing him the bottle. “Cover it as much as you can, and let me know when you are ready.”

Byleth gets his hand slick, and begins stroking himself with it, overwhelmed by the sensation after ignoring his body for so long. It is like torture, doing this and knowing that he can’t finish himself, but he manages to do only as she tells him. Rhea has stopped fingering herself now, and has turned around to face him, a warm smile on her face as she says, “You have done very well so far. You have resisted temptation, so now it is time for the next step. Now, I will do what I can to draw out your sin and cure you of your distractions.”

Byleth swallows hard, nodding, and Rhea turns around again as she backs up to him, spreading her asscheeks as she moves to sit on his lap. He reaches out to help keep her steady, doing only what is necessary to support her, but otherwise leaving this entirely in her hands. She begins to sink down on the tip of his cock, and as soon as he feels himself beginning to penetrate her, he has to bite the inside of his cheek, stifling a moan as he fights against the urge to take full control.

Rhea is slow as she eases onto him, and so tight that he can barely stand it. She is perfect in every way, and the teasing is driving Byleth absolutely insane. As he penetrates her, he feels as though he could cry from how much he needed this, and perhaps for much longer than he had ever realized. He groans in ecstasy when she has finished taking a seat on his lap, when he has filled her tight ass completely, and wonders what he is meant to do next.

“You should be left completely free of sin and distraction once I’m done with you,” Rhea says. “Do you understand, Byleth?”

“I-I understand...Lady Rhea,” he says, his voice barely working at this point. He has a fear that she might remain still and torture him like that, and he does not know if he will be ablet o maintain his self-control at that point, which may result in even more severe punishments. And, in his lustful daze, he begins to think that anything would be worth it, just as long as he gets to fuck the archbishop’s ass properly.

“I sincerely hope that you do,” she replies, and to his relief, she lifts herself a bit before slowly sinking back down on him, sending shocks of pleasure all throughout his body. “Now, Byleth, do you think you can recite your prayers?”

“A-ah! Which...which prayers would you like?” he gasps, not even sure if he is in the right frame of mind to remember anything like that. But he has been given a direct order from her, and in the position he is in now, he would do anything if only it meant that she would not stop.

“From today, of course. You do remember what day it is,” she says, and it is not a question. Byleth runs through prayers in his mind, trying to remember the special prayers for Saint Seiros Day, and does his best to recite them with Rhea slowly rising and falling on his lap, creating one hell of a distraction. He stammers and stumbles over his words, and whenever he pauses for too long, she will stop until he starts again, and whenever he makes a mistake, she will pick up the pace, making it far more difficult for him to remember his correction. Rhea must know that, and must intend for this to be quite the challenge for Byleth, a challenge he is not sure he can overcome.

But whatever may happen, he does not want her to stop at any cost. So he does his best to stammer out his prayers, imploring Saint Seiros for her blessing and guidance, for her assistance in helping his voice reach the goddess, so that he might be forgiven for his sins and so that he might receive blessings in the days to come. “M-may you always...a-ah! May you always watch over me, Saint Seiros!” he groans, finishing the prayer, and Rhea grinds back on him as he does, overwhelming Byleth as she does.

“Very good,” she says, rather breathless, “but not nearly good enough, I’m afraid. You can never hope for your voice to reach Saint Seiros when you sound so unsure of yourself. Your distraction is so obvious that even if you could reach her, you may offend her. Please, start over.”

“B-but, Lady Rhea…” It takes a lot out of him just to be able to protest, so he is not sure how she expects him to run through his prayers again, and with less mistakes than before. Especially not now that she has taken to bouncing up and down on his lap, riding his cock in such a way that she makes it impossible to think about anything other than her. How could he be expected to care about Saint Seiros at a time like this?

But Rhea insists, and when he protests, she stops entirely and says, “Byleth, I hope you know that the more severe punishments for your actions are not nearly as pleasant as this one. I had sincerely hoped that you would be able to repent through these methods, but if you insist on defying, then more drastic measures may have to be taken.”

Though she does not go into detail, he is sure that that means something truly unpleasant, rather than the fun that they have been having, the fun that hardly seems like a punishment or a means of celebrating this religion at all. Perhaps if he does not prove himself like this then he will be deemed a lost cause and passed off to undergo genuine torture, or relieved of his duties teaching her and cast out of the church forever. Byleth had never considered possibilities like those before, but now, with his head too cloudy to think properly, he begins to fear.

“I will try again,” he says in a low voice, not wanting to have to stop, and not wanting to have to undergo serious punishment. “S-Saint Seiros, please hear my prayer…” he begins, his voice already shaking from the strain of it all. Rhea resumes bouncing on top of him, quickly making focus impossible, and as he stammers his way through his prayer, he finds himself making even more mistakes than before, getting it mixed up with the others, be it regular ones for daily sermons, or prayers directed at other saints.

Rhea seems especially frustrated when he lets another saint creep in, grinding down on him so much so that he nearly loses control when he accidentally switches off to Saint Cethleann. By the time he has reached the end, begging Saint Seiros to watch over him, she is moaning and working her ass on his cock with such ferocity that he knows he can no longer hold back, jerking his hips up reflexively as he lets go, filling her ass as he comes hard.

For a moment, he is so lost in the haze that he does not think about the consequences of his actions, but then, when he realizes what he has done, he begins to fear. Rhea is silent, catching her breath the same as him, and he waits for her verdict. After she has steadied herself, she says, “It saddens me to say that you still show so many signs of distraction. I’m not sure what else I can do for you, Byleth.”

“P-please, I can-” he starts, but she interrupts him.

“If that was not enough to draw out your sin, then I know of only one other method before we have to resort to more drastic measures,” Rhea continues, before climbing off of him. “Byleth, are you truly serious about this?”

“I am, Lady Rhea,” he insists. “Whatever it takes, I promise that I will prove that to you.”

“I sincerely hope that is true,” she replies. She is now facing him, and it is once again hard to describe the expression on her face. Byleth has no idea what she plans to do, until she begins to climb on his lap again, and suddenly, he understands perfectly.

To him, this seems far more like a reward than a punishment, but he is not going to protest that now, especially not as she begins to straddle him, teasing the tip of his cock and causing him to gasp out, tensing in response.

“This is all for the sake of Saint Seiros,” Rhea says. “We are honoring her today.”

Byleth wants to say something about it being Rhea’s birthday as well, that this is as much for her in his eyes as it is any saint, but he knows better, and instead says, “I do this to honor Saint Seiros.”

With that, Rhea sinks down onto him, suddenly impaling herself on his cock, and she moans out, loud and unrestrained. Like this, Byleth can see the expression on her face when he penetrates her and when she moans, something that he could only wonder about before. He is not sure how this will help keep mind off of earthly distractions, when Rhea is the only thing that he can look at and the only thing that he could hope to think about right now.

She wraps her arms around his neck and murmurs, “Now, do what you must to rid yourself of sin.”

“B-but, Lady Rhea,” he mumbles, hardly able to speak in his current condition. “Do you want me to...to try my prayers again, or…”

“No, nothing like that, Byleth. I want you to act on impulse, and work out all of your distractions and frustrations. As long as it is for her sake, I can hope that this will be enough to free you of your sins.”

She does not have to tell him twice. Byleth has struggled enough as it is to hold back, and now that he has an invitation to give in to everything that he wants to do to her, he has no choice but to go along with it. He holds on Rhea’s wide hips, looking up into her eyes as he pushes up into her, watching the way her expression shifts as she moans for him again. As long as she is around, he is sure that he will never be free of sin.

His pace soon becomes erratic as he begins, because once he has started to fuck her, once he has cut loose, he finds it hard to restrain himself. He had done the best he could while she rode him with her ass, but now that she has given him free reign, he finds that all he can do is thrust wildly up into her, bucking his hips and moaning, making sounds that he has never made before, that he never even knew he was capable of.

All the while, Rhea moans along with him, bouncing on top of him and praising him through her moans. “Yes, Byleth, like that! Let everything out of you at once!” she orders, and he fucks her harder in response.

He grits his teeth as he drives into her, overwhelmed by how tight she is and how beautiful she is, how beautiful her body is, and how damn  _ sexy _ she is. Honestly, he doesn’t understand how anyone is meant to focus on their faith, or rid themselves of sinful thought, when the very symbol of their church is a woman like Rhea.

He is barely conscious of himself speaking when he groans her name, “Ah...L-Lady Rhea…”

“Not right now,” she murmurs, and he does not understand what she means. “Please, call me Seiros…”

In his hazy state, Byleth does not question her, thinking only of his promise to do this for the sake of honoring the saint. Though it might not make much sense to him otherwise, in this moment, he can only assume that speaking to Rhea as if she were Seiros herself is meant to help him. And, really, if he were to question that, it would also make sense to question why any of this would help him, and he has no intention of questioning that when he has enjoyed it so much.

“Yes, Lady Seiros,” he manages to gasp out, knowing that it won’t be long for him now. And Rhea- his saint, at least for right now- has grown more tense at his words, her moans coming louder and more frequently as she grinds down on him, desperate for more, and Byleth holds tight to her, thrusting harder to help bring her to climax.

When Rhea comes, she cries out for Byleth, and the sensation is enough to push him over the edge. His thoughts are so cloudy and he is so dazed that, in the moment he comes inside of her, holding tight to her and calling out for Saint Seiros, he almost thinks he sees a resemblance between the two of them.

But then he slumps back, exhausted and blissful, and Rhea relaxes on top of him, letting him hold her for a while. He forgets the purpose of meeting with her until she says, “I’m not sure if that was enough, professor.” Feeling him tense in worry, she laughs and says, “You have nothing to be afraid of. I just think we may have to keep this up regularly, to make sure that you stay purged of sin.”

**Author's Note:**

> If you're interested in my writing updates, please follow my fanfiction twitter @WattStalf  
> 


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